Modulating fuel control apparatus



United States atent MODULATING FUEL CGNTRGL APPARATUS Charles E. Hajny, Milwaukee, Wis, assignor to Base Inc., Milwaukee, Wis, a corporation of Wisconsin Application September 4, 1953, Serial No. 378,491 31 Claims. (Cl. 236-9) This invention relates to improvements in modulating fuel control apparatus.

It is well recognized that modulation of the fuel flow to the burner of a heating plant in accordance with the heat loss from the space heated is not only an efficient method of heating, but it also provides the greatest comfort for the occupants of said space. Fuel modulating apparatus developed heretofore has generally been relatively complicated and expensive, and certain apparatus has not been entirely satisfactory from an operational standpoint. For example, certain prior devices make no provision for safety shut-off of the fuel on ignition or pilot burner outage, thus requiring'that a separate safety shut-off valve be used in the fuel line upstream from the modulating control device. Certain other devices utilize valves in parallel arrangement, thus doubling the possibility of leakage through the device. Still other prior control devices require line power for their operation, and are therefore dependent upon an electrical utility.

It is a principal object of the present invention to provide an improved modulating fuel control apparatus which is efficient in operation, and yet is relatively simple and compact in construction, and inexpensive to manufacture.

Another object of the invention is to provide a modulating fuel control apparatus of the character described which provides for safety shut-off of the fuel on outage L lating fuel control apparatus of the aforementioned character which is self-powered and is therefore independent of any electrical utility in its operation.

Another object of the invention is to provide an improved modulating fuel control apparatus of the class described having an on-olf valve and a modulator valve in series, both of said valves being actuated by a single condition responsive, for example temperature responsive, actuating mechanism.

More specifically, an object of the invention is to provide an improved modulating fuel control apparatus of the character described wherein the on-off valve is actuated by a snap-acting member carried by the modulator valve, there being force transmittingconnections with the modulating mechanism, whereby said on-off valve issnapped open and said modulator valve is thereafter modulated to open position when the modulating mechanism calls for heat, said modulating mechanism being responsive to a predetermined rise in temperature to gradually close said modulator valve and thereafter snap the on-off valve closed to stop all fuel flow to the burner.

Another specific object of the invention is to provide an improved modulating fuel control apparatus of the aforementioned character wherein there is a spring-loaded lost-motion force transmitting connection between the onofi' valve and the snap-acting member, permitting closure of said on-off valve by a thermoelectrically powered safety shut-01f mechanism on pilot burner outage, while the condition responsive modulating mechanism and said snap-acting member tend to hold said valve open.

burner 2, to control the flow of fluid to said burner. The.

device 1 includes an on-off valve 3 and a modulator valve 4, serially arranged in the fuel stream, there being safety shut-01f means 5 positioned to actuate the on-ofi valve 3, and there also being a condition responsive, for.

example temperature responsive mechanism for actuating said on-off and modulator valves.

More specifically the control 'device 1 has a body or casing comprising a pair of casing sections 7 and 8 sealingly connected, as by screws 9, with a gasket 10 interposed therebetween. The casing sections 7 and 8 provide'an inlet chamber 11, an outlet chamber 12 and an intermediate chamber 13. A transverse partition 14 sep-.

arates the chamber 11 and 13 and is provided with a central aperture 15. A partition 16 separates the cham-.

bers 12 and 13 and is provided with a central aperture 17, as well as with a smaller bypass bore 18. An adjustment screw 19 is mounted in a threaded bore 20 in the casing section 8 and controls the amount of fuelwhich can flow through the bypass bore 18 for a purpose to be hereinafter described.

The partition 14 is provided with a flat annular valve seat in the chamber 11 at the margin of the aperture 15,

and a valve member 21 coacts with said. seat to form the on-ofii valve 3. The valve member 21 may have a facing 22 of resilient material formed with an annular peripheral head for sealing engagement with the partition 14. The valve member 21 is biased toward closed position by a coiled compression spring 23;

The partition 16 is provided with a flat annular'valve seat in the chamber 13 at the margin of the aperture 17,- and a valve member 24 coacts with said'valve seat to.

form the modulator valve 4. The'valve member 24 has a central. aperture 26 and may have an annularlmetallic bead 25 for engagement with the valve seat provided by the partition 16. An inverted cup-shaped fitting 27 is pressed on or otherwise suitably fixed to the valve mem-' Connections are provided for actuation of the on-off valve 3 by the actuating mechanism 6, said means in-' cluding a snap-acting member 32 which may take the form of a snap-disk positioned within the fitting 27 and. bowed away from the concave surface '30'wh'en'in its stable undeformed state. The periphery of the disk 32 engages the periphery of the surface 30, and a circular dished member 33 is positioned within the fitting 27 and has a raised peripheral bead 34 coaxially engaging the disk 32 a short distance radially inwardly from the pe A valve stem 35 is connected riphery thereof, as shown. to the valve member 21 and extends loosely through the aperture 29 in the end wall 28, said stem being engageable by the snap-acting member 32 when the latter is snapped to upwardly bowed unstable condition, opening the on-oif valve 3 when so engaged.

Means are provided for; closing the on-olf valve 3' when the snap acting member 32 is bowed upwardly,

and tends to hold said valve 21 open. This means-takes theform of a springload lost-motion connection between the stem and the valve member 21. In the illustrated embodiment this connection is telescopic. The stem 35 is formed with a tubular section 36 of enlarged diameter, having an open upper end provided with an inturned annular flange 37'. A steni38, which may be integral with the valve 21 axially slidably projects through the open end of a tubular section 36 and has a retaining member, for example a washer 39, fixed thereto within the section 36. The member 39 is engageable with the underside of the flange 37 to prevent withdrawal of the stem 38 from the section 36. A coiled compression spring 40 is disposed coaxially. within the tubular section 36 and biases the member 39 into engagement with the flange 37.

The condition responsive modulating or actuating mechanism 6 comprises a casing 41 which is removahly fixed to the casing section 8, as by screws 42, said casing having a top wall 43 sealingly closing the open lower end of the chamber 12. A hearing sleeve 44 is carried by the wall 43 and projectsthrough the chamber 12 into the aperture 17 as shown. A stem 45 is axially slidably positioned in the bearing 44, having its lower end projecting into the casing 41, and having its upper end projecting through the aperture 26 of the valve member 24 into contact with the dished member 33 within the fitting 27. Within the hearing 44, the stem 45 is formed with an external annular groove 46 which receives a resilient sealing ring 47 to provide a gas tight seal between the bearing 44 and stem 45. A collar 48 is fixed to the stem 45 above the bearing sleeve 44, and is spaced from the valve member 24, as shown, when the snap acting member 32 is in its stable undeformed state.

An end wall 49 of the casing 41 is formed with a circular aperture 50 to receive the externally threaded open end portion 51 of a tubular fitting 52 disposed within said casing. The fitting 52 has a centrally apertured end wall 53, and has an external annular shoulder 54 in abutment with the casing end wall 49 at the margins of the aperture 50. An annular spacer 55 surrounds the threaded portion 51 of the fitting 52 and abuts the outer surface of the wall 49 said spacer having a peripheral slot 56 as shown. The fitting 52 is held in position by a nut 57 which is threaded on the portion 51 and engages the spacer 55, clamping said spacer and the end wall 49 between said nut and the shoulder 54. The threaded end portion 51 is provided with a longitudinal slot 58, with which the slot 56 of the spacer 55 is in registry.

A condition responsive, for example temperature responsive, expansible and contractible bellows assembly 59 is positioned coaxially within the fitting 52 and comprises a bellows 60 having end fittings 61 and 62 closing the opposite ends thereof in hermetically sealed relationship. The end fitting 62 is provided with a guide sleeve 63 which projects coaxially within the bellows 60 and is provided with a cross bore 64. The end fitting 61 has a stem portion 65 telescopically slidably within the sleeve 63 of the end fitting 62. The end fitting 61 also has an external stem portion 66 which slidably projects through the aperture in the end wall 53 of the fitting 52 and may have a flattened end portion 82. A coiled compression spring 67 surrounds the stem 66 within the fitting 52 and biases the bellows end fitting 61 toward the end fitting 62.

Means are provided for adjusting the position of the bellows assembly 59 within the fitting 52 to thereby provide a range adjustment. A manually engageable knob 68 is internally threaded on the portion 51 of the fitting 52, and a set screw 69 is coaxially threaded through the knob 68 and engages the bellows end fitting 62 as shown. The screw 69 may be locked in place relative to the knob 68 by a locking or jam nut 70. The knob 68 may be provided with a peripheral projection in the form of a screw 71 threaded radially thereinto and positioned for engagement with a tongue 72 projecting from the casing 4 end wall 49 to limit the rotation of the knob 68, and hence the amount of manual adjustment of the bellows position. The setting of the adjustment screw 69 relative to the knob 68 is preferably made at the factory.

A bell crank lever provides a force transmitting connection between the stems 66 and 45. The lever 80 may be channel-shaped in transverse cross-section and is pivotally mounted on a pin 81 which may be carried by the side walls of the casing 41. The web portion of one arm 83 of the lever 80 is apertured to permit passage therethrough of the portion 82 of the stem 66. The side flanges of the arm 83 are slotted adjacent the stem portion 82, as at 84, and a pin 85 extends through said stem portion and is disposed in the notches 84 as shown. The other arm 86 of the lever 80 engages the lower end of the stem 45.

A passage 73 in the end fitting 62 communicates with the bore of the guide sleeve 63, and a tube 74 afiords communication between the passage 73 and a temperature sensing bulb '75. The tube 74 has its inner end sealingly positioned in the passage 73 and extends radially outwardly through the slots 58 and 56 as shown. The bulb 75 is preferably located at the comfort level in the space being heated by the burner 2, for example at the normal location for a room thermostat. With suitable adjustment, however, the bulb 75 may be mounted in other locations, for example in the cold air return of the heating unit.

The bellows assembly 59 is commonly known as the solid-liquid fill type, the bellows 60, tube 74 and bulb 75 being filled with a liquid having a high coeflicient of expansion and having a boiling point at working pressure which is above the highest ambient temperature to which said fill might be exposed. The fill exists substantially entirely in the liquid phase, as differentiated from fills which exist in the vapor phase as well as the liquid phase. A solid-liquid fill bellows provides actuating forces which result from thermal expansion of liquid fill only, whereas bellows utilizing a fill existing in both the liquid and the vapor phase provide actuating forces produced by vapor pressure. Chloroform is illustrative of a type of liquid well adapted for use as a fill in the bellows assembly 59.

At the upper end of the illustrated control device 1, the safety shut-off mechanism 5 is mounted in a tubular extension 87 of the casing section 7. A cover plate 88 and gasket 89 sealingly close the open end of the tubular extension 87 and are fixed thereto, as by screws 90. The plate 88 is centraliy bored as at 112 and is formed with an external cylindrical socket 91. The safety shut-off mechanism 5 comprises a cylindrical hood or casing 111 axially slidable within the bore of the tubular extension- 87 and having a stem 92 fixed thereto and projecting axially through the central bore 112 and socket 91 of the plate 88. A manually engageable reset button 93 is fixed to the outer end of the stem 92, as by a pin 94, and is telescopically slidable within the socket 91. An annular packing ring 95 surrounds the stem 92 in the base of the socket 91, and a washer 96 surrounds the stem 92 and.

overlies said packing. A coiled compression spring 97 also surrounds the stem 92 and is interposed between the reset button 93 and the washer 96 to bias said button and the hood 111 upwardly toward the raised position shown, While at the same time compressing the packing 95 to effect a seal between the stem 92 and the plate 88.

Fixed within the hood 111 is an electromagnet comprising a U-shaped frame 98 having a coil 99 wound on the legs thereof. One end of said coil may be grounded to the hood 111, as at 100, and the other end of said coil extends through a suitable aperture in said hood and is connected to an insulated terminal tip 101 exposed externally within an internally threaded socket 102 formed on the exterior of the tubular extension 87. Electromagnet coil 99 is normally energized by current form a thermoelectric generator 103, one terminal of which is grounded and the other terminal of which is connected in circuit with the terminal tip 101 by means of a suitable conductor 104. The generator 103 is subject to the heat of the flame of a pilot burner 105 which is mounted in coacting proximity to the burner 2 and generator 103.

The lower end wall of the hood 111 is provided with a bearing 106, and a stem 107 is axially slidable in said bearing, being connected at its upper end to an armature 108 which is movable toward and away from the pole faces of the magnet frame 98. Externally of the hood 111 the stem 106 has a collar 109 fixed thereto, and a coiled compression spring 110 surrounds said stem between the bearing 106 and the collar 109, said spring biasing the stem 107 and armature 108 downwardly away from the pole faces of the magnet frame 98. As long as the pilot burner 105 is functioning, the coil 99 is energized by current from the generator 103, and the armature 108 is held in contact with the pole faces of the magnet frame 98 against the bias of the spring 110. On outage of the pilot burner 105, however, the coil 99 is deenergized, and the armature 108 is pulled out of contact with the pole faces of the magnet frame 98 by the bias of the spring 110. Simultaneously, the lower end of the stem 107 is moved into contact with the valve member 21 to close said valve if it is open.

To reset the safety shut-off mechanism 5, the pilot burner 105 must be functioning properly so that the coil 99 is energized by current from the generator 103. The reset button 93 is depressed, to thereby move the hood 111 and magnet frame 98 downwardly, against the bias of springs 97 and 110, to thereby move the pole pieces of said magnet frame into contact with the armature 108. Upon release of the reset button 93, the spring 97 re turns the hood 111 to the position shown, the attractive force of the energized electromagnet holding the armature 108 in contact with the pole pieces of said magnet to draw said armature and the stem 107 upwardly with said hood to the position shown, thereby maintaining the spring 110 in compressed condition. It is apparent that the stem 107, when in the raised position, permits the valve member 21 to be opened.

. The operation of the improved apparatus is as follows:

Assuming a condition where the parts of the improved device 1 are disposed as shown in the drawing so that all the fuel to the burner 2 is shut off and the room temperature is dropping. As the temperature drops, the fill within the bellows 60 contracts and permits the spring 67, acting through the stem 66 and lever 80, to push the stem 45 upwardly against the dished member 33. The spring 31 resists this initial lifting force which, acting through the snap-acting member 32, tends to lift the fitting 28 and the valve member 24. As a result, the snap-acting member 32 is snapped to its upwardly bowed, unstable condition (not shown). As the member 32 snaps upwardly it engages the stem 35 lifting the latter and the valve 21 against the bias of the spring 23. The loading spring 40 in the lost-motion connection is strong enough to withstand the compressive force exerted thereon during opening of the valve 21 without substantial compression. Fuel is now permitted to flow from the chamber 11 through the aperture 15 and chamber 13, and through the bypass 18 to the burner 2. The amount of fuel which can fiow through the bypass 18 is sutficient in quantity to permit safe ignition of the fuel at the burner 2.

If the temperature within the room should continue to drop, the fill in the bellows 60 continues to contract, and the collar 48 on the stem 45 is lifted into engagement with the valve member 24. Continued upward travel of the collar 48 lifts the valve member 24 off its seat permitting additional gas flow to the burner through the aperture 17, the amount of lift of the valve member 24, and hence the amount of fuel flowing to the burner 2, gradually increasing with decreasing temperatures. As the temperature in the room begins to rise, the bellows fill begins to expand against the bias of the spring 67,

and the valve member 24 is moved in a closing direction by the spring 31. The valve member 24 is modulated by the mechanism 6 between a maximum flow permitting open position (not shown) and the closed, minimum flow permitting position shown to supply just enough fuel to the burner 2 so that said burner supplies just enough heat to the room to compensate for the heat lost from'the room. If the amount of fuel which can flow through the bypass 18 alone is more than suificien't to supply the heat lost from the room, the room heats up and the bellows fill expands to the point where lifting force exerted by the stem 45 on the dished member 33 is overcome by the snap-acting member 32,, which thereupon snaps to the normal, downwardly bowed, stable position shown. Return of the snap-acting member 32 to its stable position permits the valve member 21 to be snapped closed under the bias of the spring 23, thereby shutting off all fuel flow to the burner 2. i

If, during normal operation of the main burner 2, the pilot burner should become extinguished, the electromagnet of the safety shut-01f mechanism 5 is deenergized, and the armature 108 is pulled from the pole pieces of the magnet frame 98 by the spring 110. 'At the same time the lower end of the stern 107 engages and pushes downwardly on the valve member 21, closing said valve member and compressing the loading spring 40 in the lostmotion connection between the valve member 21 and the snap-acting member 32. Safety shut-off of the fuel is thus provided, the aforementioned lost-motion connection permitting closure of the valve member 21 by the safety shut-oft mechanism 5 at any time that said valve member is held open by the modulating mechanism 6.

The illustrated form of the invention has been selected for the purpose of disclosure only and is not intended to define the limits of the invention. Various changes and modifications may be made without departing from the spirit of the invention, and all of such changes are contemplated as may come within the scope of the appended claims.

What is claimed as the invention is:

l. Modulating apparatus for controlling the flow of fuel to a fluid fuel burner comprising: ignition means for said burner; a thermoelectric generator subject to the heat of said ignition means; an on-oif valve biased toward a closed position and movable to an open position; a flow-controlling member biased toward a minimum flow permitting position and movable to a maximum flow permitting position; condition responsive actuating mechanism for opening said on-oif valve and modulating said flow-controlling member between said minimum and maximum flow permitting positions in response to predetermined changes in the condition; and safety shutoff means powered by said thermoelectric generator and having a movable member engageable with said on-off valve for closing the latter on outage of said ignition means, there being a yieldable connection between said actuating mechanism and said on-oif valve, whereby said movable member can effect said closure on outage of said ignition means irrespective of the response of said actuating mechanism to the ambient condition.

2. Modulating apparatus for controlling the flow of fuel to a fluid fuel burner, comprising: ignition means for said burner; a thermoelectric generator subject to the heat of said ignition means; an on-oif valve biased toward a closed position and movable to an open position; a flow-controlling member biased toward a minimum flow permitting position and movable to a maximum flow permitting position; condition responsive actuating mechanism for opening said on-olf valve and modulating said flow-controlling member between said minimum and maximum flow permitting positions in response to predetermined changes in the condition; and safety shut-off ing a movable member engageable with said on-ofi valve to, close the latter on outage of said ignition means, there being a spring loaded lost-motion connection between said actuating mechanism and said on-off valve, whereby said movable member can effect said closure on outage of said ignition means irrespective of the response of said actuating mechanism to the ambient condition.

3. In a fuel control device, the combination of: a normally seated valve member; a snap-acting member having a normal stable condition and a deformed unstable condition to which it is movable with a snap action; an on-off valve having a portion positioned to be actuated by said snap-acting member to cause opening of said on-oif valve when said snap-acting member is snapped to said unstable condition; actuating means having a portion positioned to actuate said snap-acting mem ber to said unstable condition and open said on--ofl valve when said actuating means is moved a predetermined amount in one direction, said actuating means also having a portion positioned to unseat said first-mentioned valve member by further movement of said actuating means in said direction and after snapping of said snap-acting member.

4. In a fuel control device for controlling the flow of fuel to a fluid fuel burner, the combination of: ignition means for said burner; a thermoelectric generator subject to the heat of said ignition means; a valve member biased toward a seat; a snap acting member having a normal stable condition and a deformed unstable condition to which it is movable with a snap action; an onoff valve having a spring loaded lost-motion connection with said snap-acting member to normally cause opening of said on-off valve when said snap-acting member is snapped to said unstable condition; actuating means having a portion positioned to actuate said snap-acting Q member to its unstable condition and to thereby open said on-oif valve when said portion is moved a predetermined amount in one direction, said actuating means also having a second portion positioned to actuate with said valve member upon further movement of said firstmentioned portion in said direction, to thereby move said valve member off said seat against said bias; and safety shut-off means powered by said thermoelectric generator and positioned to close said on-ofi valve on outage of said ignition means, said spring loaded lost-motion connection permitting said valve closure While said snapacting member is in its unstable condition.

5. In a fuel control device, the combination of: a valve member biased toward a seat; a snap-acting member having a normal stable condition and a deformed unstable condition to which it is movable with a snap action; an on-ofl valve in series with said valve member and having a yieldable force transmitting connection with said snap-acting member affording opening of said onoif valve when said snap-acting member is snapped to said unstable condition; condition responsive actuating means having a portion positioned to actuate said snapacting member to its unstable condition and to thereby open said on-off valve in response to a predetermined change in the condition, said acting means also having a portion positioned to actuate said valve member upon continuation of said condition change to move said valve member oil said seat against said bias to a modulated open position corresponding to the condition; and overcalling control means having a member movable from a first position to a second position wherein it engages said on-oii valve to hold the latter closed regardless of th condition of said snap-acting member.

6. In a control device for controlling the flow of fuel to a fluid fuel burner: ignition means for said burner; a thermoelectric generator subject to the heat of said ignition means; a valve member biased toward a seat; a snap acting member having a normal stable condition and a deformed unstable condition to which it is movable with a snap action; an on-ofl valve having a spring loaded lost-motion connection with said snap-acting member to normally cause opening of said on-ofl valve when said snap-acting member is snapped to said unstable condition; condition responsive actuating means having a portion positioned to actuate said snap-acting member to its unstable condition and to thereby open said on-ofi valve in response to a predetermined change in the condition, said actuating means also having a portion positioned to actuate said valve member to move the latter off said seat against said bias to a modulated open position in response to continuation of said condition change; and safety shut-oif means powered by said thermoelectric generator and positioned to close said on-oif valve on outage of said ignition means, said spring loaded lostmotion connection permitting said valve closure while said snap-acting member is in its unstable condition.

7. Apparatus for controlling the flow of fluid, comprising first and second control members movable to first and second controlling positions, actuating means comprising a movable actuating member having a force transmitting connection with both of said control members, whereby initial movement of said actuating member in one direction actuates said first control member from its first to its second controlling position, and continued movement of said actuating member in said one direction actuates said second control member from its first toward its second controlling position, and overcalling control means having a member movable from a first position to a second position wherein it engages said first control member and holds the latter in its first controlling position, there being a yieldable portion in said force transmitting connection, whereby said movable member can hold said first control member in its first controlling position regardless of the position toward which said control member tends to be actuated by said actuating means. I

8. Apparatus for controlling the flow of fluid, comprising first and second control members movable to first and second controlling positions, condition responsive actuating means for holding said first control member in its second controlling position and actuating said second control member between its first and second controlling positions in response to normal fluctuations in the condition, and for actuating said first control member from its second to its first controlling position in response to an extreme in the condition, and overcalling control means having a member movable from a first position to a second position wherein it engages said first control member and holds the latter in its first controlling position, there being a yieldable connection between said actuating means and said first control member, whereby said movable member can hold said first control member in its first controlling position regardless of the response of said actuating means to the condition.

9. Apparatus for controlling the flow of fluid, comprising first and second control members movable to first and second controlling positions, actuating means comprising a movable actuating member having a force transmitting connection with both of said control members, whereby initial movement of said actuating member in one direction actuates said first control member from its first to its second controlling position and continued movement of said actuating member in said one direction actuates said second control member from its first toward its second controlling position, and overcalling condition responsive control means having a member movable in response to a predetermined condition from a first position to a second position wherein its engages said first control member and holds the latter in its first controlling position, there being a yieldable portion in said force transmitting connection, whereby said movable member can hold said first control member in its first controlling position regardless of the position toward which said control member tends to be actuated by said actuating means.

10. Apparatus for controlling the flow of fluid, comprising first and second control members movable to first and second controlling positions, actuating means responsive to a first condition for holding said first control member in its second controlling position and actuating said second control member between its first and second controlling positions in response to normal fluctuations in said first condition, and for actuating said first control member from its second to its first controlling position in response to an extreme in said first condition, and overcalling control means responsive to a second condition and having a movable member positioned for engagement with said first control member to hold the latter in its first controlling position unless said second condition is satisfied, there being a yieldable connection between said actuating means and said first control member, whereby said movable member can hold said first control member in its first controlling position regardless of the response of said actuating means to said first condition.

ll. Modulating apparatus for controlling the flow of fluid fuel to a burner comprising, an on-ofi valve biased toward a closed position and movable toward an open position, a flow controlling member biased toward a minimum flow-permitting position and movable toward a maximum flow-permitting position, condition responsive actuating mechanism for opening said on-oif valve and modulating said flow controlling member between said minimum and maximum flow-permitting positions in response to predetermined changes in the condition,

and safety shut-off means operatively associated with said on-ofl valve and having a member movable between operating and released positions, there being a yieldable connection between said actuating means and said on-off valve permitting movement of said on-off valve to off position by release of said safety shut-off means irrespective of the response of said actuating means to the ambient condition.

12. A fuel control device comprising first and second control members movable to first and second controlling positions, a snap-acting member movable from a first to a second over center position with a snap action, a yieldable force transmitting connection between said snap-acting member and said first control member aflording disposition of the latter in its second controlling position when said snap-acting member is in its second over center position, a movable actuating member operatively related. to said snap-acting member and second control member whereby initial movement of said actuating member in one direction snaps said snap-acting member to its second over center. position for actuation of said first control member to its second controlling position, and continued movement of said actuating member in said one direction actuates said second control member from its first toward its second controlling position, and overcalling control means having a member movable from a first position to a second position wherein it engages said first control member and holds the latter in its first controlling position regardless of the position of said snap-acting member.

13. In a valve structure: a casing having an inlet port, an outlet port, and a chamber interconnecting the ports; a pair of valves cooperating with said ports individually, and movable between open and closed positions; means biasing each of said valves to a like one of said positions; means movable gradually in response to variation of a controlling condition and capable of producing force for actuating the valves against the force of their bias; and means for applying said actuating force to both of the valves concurrently, said force-applying means being yieldable so that the force effective to actuate each valve is determined by the amount of actuating force applied to the valve relative to the resistance of the valve to'movement. i

14. In a valve structure: a casing having, for flow through the casing, an inlet port, a main-outlet port, and

a chamber interconnecting the ports; said casing having also a restricted outlet communicating with said chamber intermediate said ports; means on the casing forming a first valve seat around said main-outlet port and a second valve seat around said inlet port; a first and a second closure cooperable respectively with said first and said second seat to form therewith a first and a second valve; means mounting said closures for movement into and out of engagement with their seats to control flow through the respective ports; first resilient means biasing said first closure to seated position; second resilient means biasing said second closure to seated position; means movable gradually in response to variation of a controlling condition and capable, while said condition is varying in a given sense, of producing force for actuating the closures against the force of their bias, and, while the condition is varying in an opposite sense, of reducing said actuating force so that the closures can move under the force of their bias; and means for dividing said actuating force into two components and for applying one component to each of the closures concurrently, said force-applying means being yieldable so that the seating and unseating sequences of the closures are determined by the resultant of the forces then acting on the respective closures; the arrangement being such that, in the closing cycle of the valves, said first closure is seated before said second closure is seated so that fluid can then flow through said inlet port to said restricted port.

15. In a valve structure: a casing having an inlet port, a main-outlet port, and a chamber interconnecting the ports; said casing having also a restricted outlet communicating with said chamber; a first and a second valve cooperating respectively with said main-outlet port and said inlet port and movable between port-opening and port-closing positions; means biasing each of said valves to a like one of said positions; means movable gradually in response to variation of a controlling condition and capable of producing force for actuating the valves against the force of their bias; and means for dividing said actuating force into two components and for applying one component to each of the valves concurrently, said forceapplying means being yieldable so that the force effective to actuate each valve is determined by the component of actuating force applied to the valve relative to the resistance of the valve to movement; the arrangement being such that the force effective to actuate said first valve to closed position is more than the force effective to actuate said second valve to closed position so that, in the closing cycle of the valves, fluid can flow through said inlet port to .said restricted outlet while said mainoutlet port is closed.

16. In a valve structure: a casing having, for flow through the casing, an inlet port, a main outlet port, and a chamber interconnecting the ports; said casing having also a restricted outlet communicating with said chamber intermediate said ports; means on the casing forming a first valve seat around said main-outlet port and a second valve seat around said inlet port; a first and a second clo-' sure cooperable respectively with said first and said second seat to form therewith a first and a second valve, said closures being movable in opposite directions into and out of engagement with the seats to control flow through the respective ports; means biasing each of said closures in a like one of said directions; means movable gradually in response to variation of a controlling condition and capable of producing force for actuating said closures against the force of their bias; and means for dividing said actuating force into two components and for applying one component to each of the closures concurrently, said force-applying means being yieldable so that the force effective to actuate each closure is determined by the component of actuating force applied to the closure relative to the resistance of the closure to movement; the arrangement being such that the force effective to actuate said first closure to seated position is more than 11 the force effective to actuate said second closure to seated position so that, in the closingcycle of the valves, fluid can flow through said inlet port to said restricted outlet while said main-outlet port is closed.

17. In a valve structure: a casing having, for flow through the casing, an inlet port, a main-outlet port, and a chamber interconnecting the ports; said casing having also a restricted outlet communicating with said chamber intermediate said ports; means on the casing forming a first valve seat around said main-outlet port and a second valve seat around said inlet port; a first and a second closure cooperable respectively with said first and said second seat to form therewith a first and a second valve; means mounting said closures for movement into and out of engagement with their seats to control flow through the respective ports; first resilient means biasing said first closure to seated position; second resilient means of the two-way snap-acting type biasing said second closure to seated posit-ion; means movable gradually in response to variation of a controlling condition and capable, while said condition is varying in a given sense, of producing force for actuating the closures against the force of their bias, and, while the condition is varying in an opposite sense, of reducing said actuating force so that the closures can move under the force of their bias; and means for dividing said actuating force into two components and for applying one component to each of the closures concurrently, said force-applying means being yieldable so that the seating and unseating sequences of the closures are determined by the resultant of the forces then acting on the respective closures; the arrangement being such that, in the closing cycle of the valves, said first closure is seated before said second closure is seated so that fluid can then flow through said inlet port to said restricted port.

18. In a valve structure: a casing having an inlet and an outlet, and a fluid passage interconnecting said inlet and outlet; first and second valves in series relation in said passage and movable between open and closed positions; said casing having also a restricted by-pass passage around one of said valves; means biasing each of said valves to a like one of said positions; means including means movable gradually in response to variation of a controlling condition for producing force for actuating the valves against the force of their bias; and means for applying said force to both of said valves concurrently, said force-applying means being yieldable to afford, in the closing cycle of the valves, closure of said one of said valves before closure of the other of said valves so that fluid can flow from said inlet to said outlet through said by-pass and said other valve while said one valve is closed.

19. In a valve structure: a casing having an inlet and 'an outlet, and a fluid passage interconnecting said inlet and outlet; first and second valves in series relation in said passage and movable between open and closed positions; means biasing each of said valves to a like one of said positions; said casing having also a restricted by-pass passage around one of said valves; means including means movable gradually in response to variations of a controlling condition and capable of producing force for actuating the valves against the force of their bias; and means for dividing said actuating force into two components and for applying one component to each of the valves concurrently, said force-applying means being yieldable so that the force effective to actuate each valve is determined by the component of actuating force applied to the valve relative to the resistance of the valve to movement; the arrangement being such that the force eflective to actuate said one valve to closed position is more than the force effective to actuate the other valve to closed position so that, in the closing cycle of the valves, fluid can flow from said inlet to said outlet through said by-pass and said other valve while said one valve is closed.

20. In a fluid flow-control device, the combination of first and second normally seated valves in series relation, means defining a by-pass passage around one of said valves, and actuating means including a movable actuating member and first and second actuating portions, said first and second actuating portions being positioned to actuate said one and the other of said valves to open position in response to movement of said actuating member to one position, said actuating portions being so related to said actuating member and said valves that upon return movement of said actuating member said one valve is permitted to close before said other valve, whereupon fluid can flow through said device via said by-pass and said other valve While said one valve is closed.

21. In a fluid flow-control device, the combination of first and second normally seated valves in series relation, means defining a by-pass passage around one of said valves, actuating means including a movable actuating member and first and second actuating portions, said first and second actuating portions being positioned to actuate said one and the other of said valves to open position in response to movement of said actuating member to one position, and means for imparting snap-action to the movement of said other valve, said actuating portions being so related to said actuating member and said valves that upon return movement of said actuating member said one valve is permitted to close before said other valve, whereupon fluid can flow through said device via said by-pass and said other valve while said one valve is closed.

22. In a valve structure: means defining an elongated chamber having in communication with its opposite ends an inlet and a main outlet; a pair of valves arranged in series in said chamber so that fluid must pass through both of the valves from said inlet to said main outlet, one of the valves being adjacent the main-outlet end of the chamber and being of the type which comprises a closure positionable relative to a valve seat so as to vary and to obstruct flow, the other of the valves being adjacent the inlet end of the chamber and being of the snapaction type; said chamber having intermediate said valves a restricted outlet through which fluidcan pass when said one of the valves is closed and said other of the valves is open; and means, movable gradually in response to variation of a controlling condition, for actuating the valves in such sequence, While said condition is varying in a given sense, that said one of the valves is closed before said other of the valves is closed.

23. In a valve structure: means defining a chamber having inlet and an outlet means; first and second valves arranged in series in said chamber and movable between open and closed positions, said first valve being of the type which comprises a closure positionable relative to a valve seat so as to vary and to obstruct flow, said second valve being of the snap-action type; said chamber having a restricted by-pass around said first valve through which fluid can pass when said first valve is closed and said second valve is open; and means including means movable gradually in response to variation of a controlling condition for actuating the valves in such sequence, while the condition is varying in a given sense, that said first valve is closed before said second valve is closed.

24. In a valve structure: means defining a chamber having inlet and an outlet means; first and second valves arranged in series in said chamber and movable between open and closed positions, said first valve being of the modulator type and said second valve being of the snapaction type; said chamber having a restricted by-pass passage around said modulator valve through which fluid can pass when said modulator valve is closed and the snapaction valve is open; and means including a controlling condition for actuating the valves in such sequence that said modulator valve is closed before said snap-action valve is closed.

25. In a fl'uid flow control device, the combination of first and second valves in series relation, means defining a by-pass for one of said valves, and actuating means including a movable actuating member and first and second actuating portions, said first and second actuating portions being positioned to actuate said one and the other of said valves to open position in response to movement of said actuating member to one position, said actuating portions being so related to said actuating member and said valves that upon return movement of said actuatingmember said one valve closes before said other valve, whereupon fluid can flow through said device via said by-pass and said other valve while said one valve is closed.

26. In a fluid flow control device, the combination of a modulator valve and an on-off valve in series relation, means defining a by-pass for said modulator valve, and actuating means including a movable actuating member and first and second actuating portions, said first and second actuating portions being positioned to actuate said modulator and on-off valves to open position in response to movement of saidactuati-ng member to one position, said actuating portions being so related to said actuating member and said valves that upon return movement of said actuating member said modulator valve closes before said on-off valve, whereupon fluid can flow through said device via said by-pass and said on-oif valve while said modulator valve is closed.

27. In a fluid flow control device, the combination of first and second valves in series relation, means defining a by-pass for one of said valves, and actuating means responsive to a controlling condition and including a movable actuating member and first and second actuating portions, said first and second actuating portions being positioned to actuate said one and the other of said valves to open position in response to movement of said actuating member to one position, said actuating portions being so related to said actuating member and said valves that upon return movement of said actuating member said one valve closes before said other valve, whereupon fluid can flow through said device via said by-pass and said other valve While said one valve is closed.

28. In a valve structure: a casing having an inlet and an outlet, and a fluid passage interconnecting said inlet and outlet; first and second valves in series relation in said passage and movable between open and closed positions; means defining a by-pass for one of said valves; means biasing each of said valves to a like one of said positions; means including means responsive -to variation of a controlling condition for producing force for actuating the valves against the force of their bias; and means for applying said force to both of said valves concurrently, said force-applying means being yieldable to atford, in the closing cycle of the valves, closure of said one of said valves before closure of the other of said valves so that fluid can flow from said inlet to said outlet through said by-pass and said other valve while said one valve is closed.

29. In a valve structure: a casing having an inlet and an outlet, and a fluid passage interconnecting said inlet and outlet; first and second valves in series relation in said passage and movable between open and closed positions; means biasing each of said valves -to a like one of said positions; means defining a by-pass for one of said valves; means including means responsive to variation of a controlling condition and capable of producing force for actuating the valves against the force of their bias; and means for dividing said actuating force into two components and for applying one component to each of the valves concurrently, said force-applying means being yieldable so that the force effective to actuate each valve is determined by the component of actuating force applied to the valve relative to the resistance of the valve to movement; the arrangement being such that the force effective to actuate said one valve to closed position is more than the force effective to actuate the other valve to closed position so that, in the closing cycle of the valves, fluid can flow from said inlet to said outlet through said by-pass and said other valve while said one valve is closed.

30. In a valve structure: means defining a chamber having inlet and outlet means; first and second valves arranged in series in said chamber and movable between open and closed positions, said first valve being of the type which comprises a closure positionable relative to a valve seat so as to vary and to obstruct flow, said second valve being of the snap-action type; means defining a by-pass for said first valve through which fluid can pass when said first valve is closed and said second valve is open; and means including means responsive to variation of a controlling condition for actuating the valves in such sequence, while the condition is varying in a given sense, that said first valve is closed before said second valve is closed.

31. In a valve structure: means defining a chamber having inlet and outlet means; first and second valves arranged in series in said chamber and movable between open and closed positions, said first valve being of the References Cited in the file of this patent UNITED STATES PATENTS 1,458,090 Waldron June 5, 1923 1,919,265 Vaug-n July 25, 1933 1,983,183 Newell Dec. 4, 1934 2,076,768 Denison Apr. 13, 1937 2,164,511 Furlong July 4, 1939 2,236,559 AnderssOn Apr. 1, 1941 2,253,866 Quoos Aug. 26, 1941 2,292,830 Gauger Aug. 11, 1942 2,312,479 Ray Mar. 2, 1943 2,319,685 Jackson May 18, 1943 2,406,925 Strobel Sept. 3, 1946 2,470,996 McGrath May 24, 1949 2,672,292 Caperone Mar. 16, 1954 2,693,201 Page 'Nov. 2, 1954 2,724,409 Coffey Nov. 22, 1955 2,741,266 Grayson Apr. 10, 1956 

